Imagine you are exploring a new topic. You start by searching for relevant papers in the field. You type your query, click the search button, and end up with thousands of scientific articles, waiting to be read. How do you identify which papers to focus on?

In Europe PMC, search results can be sorted differently to help you navigate through the literature. By default, results are sorted by relevance. But how is relevance defined? Let’s look at a search example: say we are interested in oxidative DNA damage. Once you type that string into a search box, the sorting algorithm ranks all your results and displays them in order. The algorithm takes into account how often search terms are found in the text. A document that mentions “DNA” ten times is likely to be more relevant to you than one with a single mention. The relevance score also depends on how many of the search terms a document contains. For instance, papers discussing “oxidative damage” or “DNA damage” are less appropriate than the ones specifically covering “oxidative DNA damage”.

Rare terms will be more relevant than common ones. Note that we expand your search by including synonyms, so whenever you search for DNA damage, you will also discover articles mentioning genotoxic stress. You can switch off synonym expansion in the advanced search, or simply place your search terms in double quotes for an exact match, e.g. “oxidative DNA damage”.

Scientific abstracts are ranked higher than articles, and papers are considered more relevant than books and other documents. Nonetheless, you can always change the type of content you are looking for via the “Popular content sets” on the right-hand side of the search results, or in the advanced search.

Using our relevance sorting, more recent publications will appear higher in the list, but if you want the latest papers over anything else, you can simply sort by date. For instance, if you are eager to see the latest manuscript from your collaborators, or the new publications from your favourite journal, just look at the most recent papers. What if, instead, you are interested in classic articles that have pioneered the field and laid the foundation for future research? Good news: you don’t need to scroll to the last page of results. Simply search by date, in reverse order. Now you can see how a scientific field has progressed.

Another way to search for foundational articles is by sorting results by times cited. Citation counts can help you find experts in the field, or help you identify the most impactful works. When ordering results by times cited, the number of citations is displayed for each paper.

With Europe PMC you can find research that matters with the click of a button. Sorting has never been easier!